1. Field of the Invention
The present invention relates to a process for producing a wear-resistant layer, in particular on components of gas turbines or aero engines which are formed at least partially from a titanium material. Moreover, the present invention relates to a component of this type for gas turbines or aero engines having a corresponding wear-resistant layer.
2. Discussion of Background Information
In the case of turbomachines, such as stationary gas turbines or aero engines, components such as rotor blades, for example, are exposed to high levels of loading on account of the prevailing external ambient conditions, with high temperatures, oxidizing and corrosive media and high rates of rotation and flow, it being possible for these high levels of loading to lead inter alia to wear, in particular fatigue wear and/or abrasive wear, to the components.
This applies in particular to components which are formed from titanium materials, the main constituent of which therefore consists of titanium. The main constituent of the chemical composition in this respect is understood to mean the chemical element of which the proportion in the chemical composition corresponds in absolute terms to the greatest proportion of the material, i.e. correspondingly titanium in the case of titanium materials. Titanium materials are also understood to mean in particular materials on the basis of intermetallic compounds, for example titanium aluminides. Correspondingly, in the present disclosure an alloy consisting, for example, of identical proportions of titanium and aluminum is also subsumed under the term “titanium material”.
Since the problem in relation to wear is already known for components of gas turbines or aero engines, there are various proposals in the prior art for protective layers, what are termed wear-resistant layers, which have the intention of reducing the wear to the components. In particular, a wide variety of coatings having a high hardness in order to thereby reduce the wear are known. The various wear-resistant layers can be applied to the components in different ways, for example by thermal spraying, build-up welding processes, physical vapor deposition (PVD) or chemical vapor deposition (CVD) or by build-up soldering processes. However, the solutions known to date often exhibit the problem that the adhesion, i.e. the bond of the wear-resistant layer to the base material of the component, is inadequate, and therefore the wear-resistant layer can become detached.
In addition, problems can occur when applying wear-resistant layers as a result of incompatibilities with the base material. In this respect, U.S. Pat. No. 8,393,528 B2, the entire disclosure of which is incorporated by reference herein, describes the application of a wear-resistant material, which is soldered onto a TiAl alloy in the form of a separately manufactured body in order to avoid the mixing of the TiAl alloy with the hard material alloy, for example a cobalt-chromium alloy, so as to thereby exclude brittle phases and cracking. However, a process of this type with the separate production of a wear-resistant component and the subsequent application of the component to the surface to be protected is very complex.
In view of the foregoing, it would be advantageous to have available a wear-resistant layer for titanium materials and also a corresponding production process which make it possible to achieve simple application and production of the wear-resistant layer combined with a good wear resistance and adhesion of the wear-resistant layer to the base material of the component.